, . . , . :
HCl + KOH KCl + H2O;
H+ + Cl- +K+ + OH- K+ + Cl- + H2O;
H+ + OH- H2O.
, . , , . :
CH3COOH + KOH CH3COO + H2O;
CH3COOH + OH- CH3COO- + H2O;
HCl + NH4OH NH4Cl + H2O;
H + + NH4OH NH4+ + H2O.
ֳ , .
, , , .
. ( ) . + ( < 7). , , , + - ( > 7).
.
1. , ͻ 7 (NaCl; Ba(NO3)2; K2SO4).
2. +:
NH4NO3 + H2O NH4OH + HNO3;
NH4+ + H2O NH4OH + H+; pH < 7.
3. -:
KCN + H2O KOH + HCN;
CN- + H2O OH- + HCN; pH > 7.
4. , 7:
CH3COONH4 + H2O NH4OH + CH3COOH;
CH3COO- + NH4+ + H2O NH4OH + CH3COOH; pH 7.
5. ó :
) K3PO4 + H2O K2HPO4 + KOH;
PO43- + H2O HPO42- + OH-; pH > 7;
K2HPO4 + H2O KH2PO4 + KOH;
HPO42- + H2O H2PO4- + OH-; pH > 7,
, - 34;
) FeCl3 + H2O FeOHCl2 + HCl;
Fe3+ + H2O Fe (OH)2+ + H+; pH < 7;
FeOHCl2 + H2O Fe(OH)2Cl + HCl;
Fe(OH)2+ + H2O Fe(OH)2+ + H+; pH < 7,
+ Fe(OH)3 ;
) (Al2S3, Cr2S3, Al2(CO3)3) . ( "-");
Cr2S3 + 6H2O = 2Cr(OH)3 + 3H2S; pH 7;
Fe(CO3)3 + 6H2O = 2Fe(OH)3 + 3H2CO3; pH 7.
3H2O 3CO2
ʳ . , NaCN:
NaCN + H2O NaOH + HCN; CN-+ 2 HCN + OH-.
,
= .
[H2O]>>[HCN], , [H2O] = const,
|
|
K .[H2O]= K = = =
= Kw / K . K r = Kw / K , K r = Kw /(K . K ).
b - br = , - .
1. K r br 0,1 Na3PO4 ( H3PO4 K 1 = 7.10-3; K 2 = 6.10-8; K 3 = 4.10-13).
:
1. 1 -? br1 -?
PO43- + H2O = HPO42-+ OH-. ó (HPO42- = H+ + PO43-) K 3.
K r1 = Kw / K 3 = 10-14 / 4.10-13 = 0,025;
br1 = = = 0,5 (50 %).
2. 2 -? b2 -?
HPO42- + H2O = H2PO41- + OH-
K r2 = Kw / K 2 = 10-14 / 6.10-8 = 1,67.10-7;
br2 = = = 1,84.10-7 (0,184 %);
C (HPO42-) = 0,1. 0,5, br1 = 50 %, 50 % Na3PO4 Na2HPO4.
³: Kr1 = 0,025, br1 = 50 %, Kr2 = 1,67.10-7, br2 = 0,184 %.